The formation of wrinkles and the loss of an elastic feeling of the skin are the indicators of skin aging, which many women are most concerned with. Therefore, the development of cosmetics excellent in the wrinkle improving effect and the elastic feeling improving effect is much needed.
Among wrinkles, fine wrinkles at the corners of the eyes and around the mouth are considered to be caused by dry skin, and it is reported that the degree of fine wrinkles is correlated with the water content in the stratum corneum in humans (non-patent literature 1). Therefore, in many cosmetics, a wide variety of moisturizers is blended in anticipation of wrinkle preventing and wrinkle improving effects. As representative moisturizers, polyols and polyethers such as glycerin, 1,3-butylene glycol, xylitol, sorbitol, polyethylene glycol, propylene glycol, and diglycerin (ethylene oxide) (propylene oxide) adduct can be listed. However, it is difficult to obtain wrinkle preventing and wrinkle improving effects only with these compounds. In addition, there has been a problem in that a sticky feeling is generated when a large amount is blended.
Polymer compounds such as hyaluronic acid, mucoitin sulfuric acid, charonic acid, chondroitin sulfate, and soluble collagen are also used widely as the moisturizer. However, a taut feeling due to a coating feeling is easily generated, and they tend to be stickier than polyols.
On the other hand, as for the elastic feeling, improvement has been attempted thus far by blending film-forming components such as polyvinyl alcohol, sodium alginate, mucopolysaccharides and collagen, eggshell protein and degradation products thereof, and acrylic resins; spherical or other powder; crosslinked methylpolysiloxane; etc. (patent literatures 1 and 2). However, it has been known that the spreadability during application becomes poor and the sticky feeling is generated when these components are blended to the extent that the elasticity improving effect is obtained.
Thus, if the above-described moisturizers and/or film-forming components are blended in large amounts, in anticipation of the improvement of wrinkles and an elastic feeling, there have been problems in that freshness is lost, even for oil-in-water emulsion compositions, and an oily feeling and sticky feeling are generated. If a large amount of ethanol is blended to eliminate the sticky feeling, the stability of emulsion particles decreases and the irritation to the skin is generated; thus it has been difficult to blend a large amount of ethanol.
Accordingly, the preparation of cosmetics, wherein the moisturizing effect is sufficiently high, the wrinkle improving effect is recognized, the skin elasticity improving effect is excellent, the spreadability during application is good, and the oily feeling and sticky feeling are absent, has been sought-after.